You will be given a definition of a task first, then some input of the task.
In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Among the entities, try to find the best entity that is most likely to fill in "_" and classify the answers based on options.

Thousands of commuters were left stranded at Waterloo station this afternoon after an earlier incident in which a person was struck by a train scuppered the entire day's services. Frustrated passengers packed the concourse this afternoon as services in and out of the city centre were delayed or cancelled. The chaos ensued after Network Rail was forced to close a section of the tracks between Wimbledon and Surbiton when a person was struck by a train. Scroll down for video Thousands of commuters were left stranded at Waterloo station during rush hour after a part closure of the track between Surbiton and WimbledonThousands were left stranded at central London station during rush hourCrucial section of track between Wimbledon and Surbiton was closedSouth West trains warned passengers of cancellations on all servicesNetwork Rail said staff were working 'flat out' to fix the situation 
 Questions:At 9pm delays of up to 30 minutes were still being experienced on _. (A) Waterloo station (B) Network Rail (C) Wimbledon (D) Surbiton (E) London (F) South West trains
Output:
(F)